Function composition in Perl 6

test.pl

sub infix:<|\>> ($f, $g) {
  -> $x {
    $f($g($x))
  }
};

my $mult_2 = -> $x { $x * 2 };
my $plus_3 = -> $x { $x + 3 };
my $compound = $mult_2 |> $plus_3;

printf("f o g (x) = %d\n", $compound(1));# => (1 + 3) * 2 =  8
printf("f o g (x) = %d\n", $compound(2));# => (2 + 3) * 2 = 10
printf("f o g (x) = %d\n", $compound(3));# => (3 + 3) * 2 = 12

FWIW, Perl6 has a function combinator operator ( link ).

If you prefer your infix |> over ∘ or o then you can just alias like so: my &infix:«|>» = &infix:«∘»;